Shrinkproofing textiles with polyamides and volatile polyepoxides



United States Patent SHRINKPROOFING TEXTILES WITH POLYAMIDES AND VOLATILE POLYEPOXIDES Thompson J. Coe, Albany, Qalifi, assig'nor to the United States of America as represented by the Secretary of Agriculture No Drawing. Application-May 12, 1958 Serial No. 734,799

4 Claims. (Cl- 8 -128) (Granted under Title 35, US. Code (1952), sec. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sub'licenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to and has among its objects the provision of novel processes for shrinkproofing and feltproofing textiles. The invention also includes the provision of improved textiles having superior qualities as to resistance to shrinking and felting. Further objects and advantages of the invention will be evident from the following description.

It is well known in the art that many textile fibers exhibit poor dimensional stability. For example, laundering causes severe shrinkage of woolen textiles. This technical disadvantage seriously restricts the applications of wool in the textile industry and much research has been undertaken in order to modify the natural fiber in order to improve its shrinkage properties. In general, known methods of treating wool to improve its shrinkage characteristics have the disadvantage that the hand of the fabric is impaired, or, if the amount of agent applied is limited to avoid impairment of hand, the degree of shrinkage protection is relatively poor.

In accordance with the invention, wool, or other textile material, is impregnatedwith a polyamide then cured by subjection to the vapors of a volatile polyepoxide. This procedure yields a product which is virtually shrinkproof under normal laundering procedures while the hand, resiliency, porosity, tensile strength, color and other valuable properties of the textile are retained. Additionally the treated textile exhibits a great improvement in resistance to creasing and wrinkling as compared to the original textile. V

The prior art discloses methods for shrinkproofing textiles by applying polyepoxides and curing the polyepoxide with various curing agents, including triethyl- :amine, ethylene diamine, dieth'yle'ne triamine and other amino compounds. The process of the invention affords many advantages over the known procedure, as follows:

(a) In the process of the invention the original color of the textile is retained. For example, white wool treated in accordance with the invention retains its White color. In the known process the treated wool develops yellowness; Dyed woolen textiles treated in accordance with the invention retain their original colors in undiminished brightness whereas the processes of the prior art cause a graying or dulling of the fabrics.

(b) The process of the invention yields products of especially soft and resilient properties andmore shrinkproofing effect is attained per unit Weight of resinous material deposited on the fibers.

(c) The curing treatment of the invention-involving contacting the polyamide-impregnated textile with a polyepoxidein the vapor phase-has the advantage that this curing agent can penetrate readily into the textileand ensure complete and uniform cure of the polyamide com- Patented June 9, 1959 2. position. Moreover, the vapor phase polyepoxide treatment does not disturb the appearance, dimensions, or construction of the textile. There is no change in nap, no wrinkling, Textiles having pleats, folds, etc. retain such forms Without change. Also, since the curinginvolves a vapor phase rather than the usual liquid treatment, no wringing 'or other mechanical treatments are required. This means that no wrinkling or other change in the construction or arrangement of the textile is in- In applying the process of the invention in practice, the textile is first impregnated with a liquid preparation containing the polyamide. The impregnation is per formed in any of the usual ways. For example, the poly- :amide composition is applied by spraying, brushing, dipping, etc. To assist in wetting the textile, it may be run through padding rolls or the like. Excess liquid may be removed by passing the textile through wringer rolls. The proportion of active material in the liquid preparation is usually so selected that there is deposited on the textile about 0.5% to 10% of its weight of the polyamide. In general, the greater the proportion of this agent, the greater will be the shrinkage protection alforded. After the textile has been impregnated with the polyamide preparation it is cured directly or dried in air prior to curing,

the latter procedure being generally preferred.

Curing of the polyarhide-impregnated textile involves subjecting it to the vapors of a volatile polyepoxide. This may conveniently be done, for example, by hanging the textile in a chamber in which is exposed an open vessel containing the polyepoxide. To increase the vapor .pressure of the polyepoxide, that is, the proportion thereof present in the atmosphere Within the chamber, the chamber may be heated, evacuated, or both heated and evacuated. No special precautions need be taken as-to addition or elimination of moisture from the system. The textile is allowed to remain in contact with the poly epoxide vapors until the polyamide is cured--that is, until it is renderedinsoluble so that it is not removable from the texti-le by laundering. The temperature within the chamber may be at room temperature or may be increased to about 150 C. to obtain faster cure. The time for cure will vary depending on 'several'factorssuch as temperature (higher temperatures promote faster cure); the nature of the'polyep oxide (more volatile polyepoxides under the'same conditions will cause faster cure); and the pressure within the curingchamber (generally a lower pressure will cause more polyepoxide to be vaporized, hence the cure will be faster). The curing operation is generally complete when the polyainide deposit on the textile increases in weight by about 10 to due to reaction of the polypoxide with the polyamide on the textile fibers producing an insoluble resinous composition thereon. No efiort is made to control the amount of polyepoxide other than to ensure that the chamber at all times contains vaporous polyepoxide so that an excess of this reagent is always available for reaction with the polyamide.

The polyamides'used in accordance with the invention are those derived from aliphatic polyamines and polybasic acids. Methods of preparing these polyamides by' condensation of polyamines and polycarboxylic acids are well known in the art and need not be described here. One may prepare polyamides containing free amino groups or free carboxylic acid groups or both free amino and free .carboxylic acid groups. Generally it is preferred to employ polyamides which contain freeai'nino groups. since the active hydrogens on't hese groups are especially reactive with the epoxy groups of the poly'epoxide to form insoluble polyepoxide-polyarn-, 1de reaction products. The polyamides may be derived from such polyamines as ethylene diamine, diethylene polyamines and polymeric fat acids. -disclosed for example by Cowan et al., Patent No. 2,450,940. Typical of these polyamides are those made by condensing ethylene diamine or diethylene triamine with polymeric fat acids produced fromthe polymerization of drying or semi-drying oils, or the free acids, or

simple aliphatic alcohol esters of such acids. The polymeric fat acids may typically be derived from such oils I as soybean, linseed, tung, perilla, oiticica, cottonseeds,

boxylic acids which may be condensed with the polyamines, to form polyamides are glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic -acid,' isopthalic acid, terephthalic acid, beta-methyl adipic acid, 1,2-cyc1ohexane dicarboxylic acid, malonic acid and the like. Depending on the amine and acid constituents and the conditions of condensation,; the poly-amides may have molecular weights varying about from 1,000 to 10,000 and melting points about from 20-200 C. Particularly preferred for the purpose of the invention are the polyamides derived from aliphatic Such products are com, tall, sunflower, safliower, and the like. As well known in the art, the fat acids combine to produce a mixture of dibasic and higher polymeric acids. Usually the mixture contains a preponderant proportion of dimeric acids with lesser amounts of trimeric and higher polymeric acids, and some residual monomeric acid. A

typical polyamide of this type is, for example, one produced by heating soybean dimeric fatty acids and diethylene triarnine.

The polyamide is preferably applied to the textile material in the form of a solution or dispersion to ensure uniform impregnation of the fibrous elements.

Aqueous solutions may be used, for example, where the selected polyamide is soluble in this medium. In many cases other volatile solvents may be required such as acetone, benzene, alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, dioxane, etc. de-

' pending on the property of the agent in question. It is often preferred to apply the polyamide in the form of aqueous emulsions prepared by application of any of the known emulsification technique. A preferred procedure is to dissolve the polyamide in a suitable quantity of alcohol or other volatile organic solvent and add this solution to water with vigorous agitation. this way contact of the solution with water will precipitate the polyamide in minute particles which will be relatively easy to emulsify. To assist in forming and maintaining the emulsion one may add a small proportion of a conventional emulsification agent. purpose one may employ agents such as soaps, longchain alkyl sulphates, long-chain alkyl benzene sulphonates, alkyl esters of sulphosuccinic acid, etc., typical examples being sodium lauryl sulphate, sodium alkyl (C -C benzene sulphonate, sodium dioctylsulphosuccinate, etc. Preferably, emulsifying agents of the non-ionic type are employed, for example, sorbitan laurate, polyoxyethylene ether of sorbitan laurate, polyoxyethylene ether of sorbitan monostearate, polyoxyethylene ether of sorbitan distearate, sorbitan trioleate, iso-octyl phenyl ether of polyethylene glycol, and so forth. Other suspending agents as gums, gelatin, pectin, soluble starch, dextrins, etc. can be used to keep the polyamide in suspension. It is obvious that the proportion of active materials in the solution or dispersion may. be varied as necessary to deposit on the textile material the desired percentage of polyamide.

Butadiene dioxide .(also designated 1, ,3,4-diepoxy- Inv For this 4 limonene dioxide. Volatile polyepoxide ethers may also be employed as for example diglycidyl ether, diglycidyl thioether, di'glycidyl etherfof ethylene glycol, and the like. In general, one may employ any volatile polyepoxide which contains at least two epoxy groups. and wherein the remainder of the polyepoxide molecule is a carbon chain or a carbon chain interrupted with ether linkages. Preferably the polyepoxides are free from functional groups other than hydroxyl groups, ether groups, and epoxy groups..

The process of the invention is particularly adapted to the treatment of wool but is also advantageously applicable to other textiles including mohair; animal hair; silk; fibers made from proteins such as zein, casein,peanut protein, soybean protein, keratins, etc.; cotton; regenerated cellulose; viscose; linen; cellulose acetate; etc. The textile material may be in the form of fibers, threads,v yarns, woven or knitted fabrics, garments, etc.

The invention is further demonstrated by the follow ing illustrative examples.

Example I Pieces of white woolen cloth were padded with emul-- sions of a polyamide. In these emulsions, the total concentration of this agent was varied (as set forth below): In each case 2% of the iso-octylphenyl ether of polyethylene glycol (Triton X-l00) was used as the emulsifying agent. The polyamide was a commercial prodnot being a condensation product of diethylene triamine and heat-dimerized unsaturated fat acids. It was a viscous liquid at ordinary temperatures with a viscosity of A -A on the Gardner-Holt scale at 25 C. and a specific gravity of 0.99 at 25 C.

The impregnated cloth samples were dried in air at 65 C. then placed in a chamber which contained an open vessel of butadiene dioxide. The samples were: exposed to the polyepoxide vapors for 72 hours at room: temperature. It was observed that all the cured samples were white in color.

The treated samples of cloth and a sample of un-- treated cloth (control) were subjected to tests to tie- In these teststhe cloth samples were subjected to a laundering operatermine their shrinkage characteristics.

tion wherein the cloth was violently agitated in an Accelerotor for 3 min. in a 0.5% solution of sodiumoleate at 40 C. with a cloth to solution ratio of l to 35. The area of the cloth was measured before and after laundering. The washing tests were carried out in duplicate. The results are tabulated below, the shrinkage values being averages of the duplicate tests.

Cone. of Pickup of Area polyamide Pickup otcured shrinkage Sample in polyamide polyamide after emulsion, by cloth, polyepoxide laundering,

percent percent by cloth, percent percent vapor phase to cure and insolubilize the polyamide on the textile fibers, the polyepoxide containing at least two groups per molecule, the remainder of the polyepoxide molecule being a member selected from the group consisting of a carbon chain and a carbon chain interrupted with ether linkages.

2. The method of claim 1 wherein the polyepoxide is butadiene dioxide.

3. The method of shrinkproofing wool Without significant impairment of its hand which comprises impregnating wool with a polyamide of an aliphatic polyamine and a polymeric fat acid containing at least two carboxyl groups, said polyamide having free amine 6 groups, the total amount of polyamide deposited on the wool being about from 0.5 to 10% of the weight of the wool and exposing the impregnated wool to a volatile polyepoxide in the vapor phase to cure and insolubilize the polyamide on the Wool fibers, the polyepoxide containing at least two epoxy Lie) groups per molecule the remainder of the polyepoxide molecule being a member selected from the group consisting of a carbon chain and a carbon interrupted with ether linkages.

4. The method of claim 3 wherein the polyepoxide is butadiene dioxide.

No references cited. 

1. THE METHOD OF SHRINKPROOFING A ATEXTILE WITHOUT SIGNIFICANT IMPAIRMENT OF ITS HAND WHICH COMPRISES IMPREGNATING THE TEXTILE WITH A POLYAMIDE OF AN ALIPHATIC POLYAMINE AND A POLYCARBOXYLIC ACID, SAID POLYAMIDE CONTAINING FREE GROUPS SELECTED FROM THE GROUP CONSISTING OF AMINE GROUPS AND CARBOXYL GROUPS, THE TOTAL AMOUNT OF POLYAMIDE DEPOSITE ON THE TEXTILE BEING ABOUT FROM 0.5 TO 10% OF THE WEIGHT OF THE TEXTILE BEING ABOUT FROM THE IMPREGNATED TEXTILE TO A VOLATILE POLYEPOXIDE IN THE VAPOR PHASE TO CURE AND INSOLUBLIZE THE POLYAMIDE ON THE TEXTILE FIBRES, THE POLYEPOXIDE CONTAINING AT LEAST TWO EPOXY 